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19-03-2007, 19:29
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#1
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Registered User
Join Date: Oct 2005
Posts: 6,190
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Chlorine Tablet Sitting in Seawater Supply Line
So my friend and I were thinking about this one, and it seems like a good idea, but I'm sure I'm not the first person to consider it.
My friend installed a new Lavac, and he loves it, but he's a little bothered that even a few weeks after having it, there's deposits on the inside of the bowl. We're not sure if it's mineral deposits or growth, but here's what we thought:
- Put a raw water strainer in the syphon(sp?) loop of the sea water intake for the head. The idea being that when pumping, all water will rush through the filter, but that the syphon loop will keep the strainer from sitting in water non stop.
- The strainer has a mix of water softeners and chlorine, so that everything after the strainer should be dead, soft, and much less damaging to the plumbing.
Am I crazy? Just thinking of a good way to improve the health of my head, hopefully through a rather cheap mechanism.
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19-03-2007, 20:20
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#2
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Moderator Emeritus

Join Date: Feb 2004
Location: Sunshine Coast, Qld, Australia
Boat: Steel Roberts Offshore 44
Posts: 5,173
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Clean Lavac...
I put in a new Lavac a few months ago and am also experiencing results similar to those you describe.
I put them down to the polluted water where the boat is and the fact that the PO put the outlet through hull in the wrong place (too close to the inlet) and made it the wrong size.
On the up side a cheap toilet brush and cleaner makes everything (almost) new again.
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19-03-2007, 20:28
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#3
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Registered User
Join Date: Dec 2006
Location: Ft. Lauderdale, Fl
Boat: Brewer 44, 44 LOA - "Lady Hawk"
Posts: 20
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Fresh Water
I switched to fresh water while docked where water is not the cleanest to avoid this problem. We eliminated odor and discoloration.
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19-03-2007, 20:32
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#4
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Registered User
Join Date: Oct 2005
Posts: 6,190
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Chris: The bowl isn't really what's worrying us, more the rest of the plumbing. But then again, there's lots of sea water plumbing on a boat (engine cooling, engine exhaust, galley drain, etc), so maybe we're freaking out about this too much.
Lady Hawk: He's probably going to switch to fresh water while docked, as you did. We've heard that really fixes a lot of the problems lickity split. That being said, I don't want to spend $300 on pumps and plumbing to "fix" a problem that will show back up in full force the minute we pull away from the dock.
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19-03-2007, 20:44
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#5
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Moderator Emeritus

Join Date: Feb 2004
Location: Sunshine Coast, Qld, Australia
Boat: Steel Roberts Offshore 44
Posts: 5,173
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Sea cocks...
I am a great believer in turning all sea cocks off when I leave the boat.
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19-03-2007, 21:36
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#6
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cruiser
Join Date: Nov 2005
Location: Vanuatu
Boat: Whiting 29' extended "Nightcap"
Posts: 1,569
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Use a standard marine toilet product regularly to reduce the build up as this will happen even if the bugs are killed. Install a "Whale Gusher" type diaphragm pump on the discharge line and evecuate all the water from the system prior to leaving the boat unattended.
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20-03-2007, 00:16
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#7
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Senior Cruiser

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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Quote:
this will happen even if the bugs are killed.
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And that is exactly what is happening. The little microscopic creatures in the saltwater die and settle out of the water. They fall to the sides of the bowl and leave this greyish scum on it. They can also stink. The only way to stop it from happening is to fresh water rinse before leaving the boat. If you are on the boat, regular flushes means the critters have an oxygen rich pond to swim in and they survive happily till the next flush when a new recruitment arrives and the oldies move on with the flow.
Doseing the toilet with Chlorine may stop the odor, but won't stop the scum unless it is strong enough to bleach, but I doubt you will want that much chlorine. It would stink just as bad.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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20-03-2007, 01:17
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#8
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Registered User
Join Date: Jul 2005
Location: new zealand
Boat: Lotus 10.6
Posts: 1,270
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and I thought the stink was me!
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20-03-2007, 01:55
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#9
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Registered User
Join Date: Apr 2006
Location: New Zealand
Boat: Hunter 340 - Whimsey
Posts: 25
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I have been on Seafox and the smell can be attributed to the owner.
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20-03-2007, 09:25
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#10
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,129
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Chlorine's a bad idea. It will attack seals, pump parts, and plastic/rubber plumbing lines. It will kill the good bacteria which are trying to keep down the stinky ones in the holding tank.
Seawater is a rich soup, so you're going to have some problems with using it in a head, no matter what you do. Rinsing or flushing with fresh water, or keeping things dry, are worth looking into if you're really picky about using that bowl as a shaving mirror.<G>
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20-03-2007, 10:53
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#11
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Moderator Emeritus
Join Date: Mar 2003
Location: Hayes, VA
Boat: Gozzard 36
Posts: 8,700
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Yes as noted by hellosailor you need to be concerned about your pipes. Do treat them badly else they will "stink trough" quicker.
No order safe hose is forever. I replaced Sadowfax's hose last season. After a very long time even with top quality hose they all need to be replaced as the "stink" eats through the tubing. When this happens there is no cure but removal. This is NOT a job you want to have any day sooner than required. Make it a very long time by treating your pipes with a little kindness. Using plenty of water keeps the build up from making it worse. Alittle vinegar to help remove the salt build up helps too. Save the harsh checmicals for your home plumbing. Even the tank treatment products should not be used to excess.
The really nasty smells are from lack of oxygen. When properly vented your tank won't have a hideous smell even if it does not smell great.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
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20-03-2007, 11:36
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#12
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Guest
Posts: n/a
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Toilet chemistry.
All of the postings so far have missed some of the basic chemistry of sea water in toilets that has to be remembered and very well might be the source of the "deposits" that you mention.
Whenever urine is added to seawater the pH changes enought that calcium carbonate ("limestone") comes out of solution. Over time this will deposit on the bowl and discharge piping. Over the course of time it will narrow the piping and eventually obstruct it. The chemistry solution is to flush acid either acetic acid in the form of vineger or dilution hydrocholic acid ("muriatic acid") on a regular basis. Neither of these are complete solutions and at some frequency you need to remove the piping and remove the brittle deposits. Traditionally this is done by wacking the tubing against a piling, making sure the "stuff" that comes out doesn't land on a neighbor's boat!
For cleaning the bowl, try a vineger soak, or any of the household products for removing lime scale. A solution of oxlic acid will also do a good job without being tough on your plumbing system. Chlorine will have no effect on lime scale.
An important note: If you use a connection to your freshwater system to flush your toilet, be sure that it is IMPOSSIBLE for water to back up into your potable system by installing some form of vacumn break. Do NOT count on water pressure alone to stop backflow.
Bill
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20-03-2007, 11:45
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#13
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֍֎֍֎֍֎֍֎֍֎
Join Date: Apr 2006
Posts: 15,129
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Bill-
Obviously with holding tanks this becomes an exercise in what's not possible...but I was taught "FLUSH TEN TIMES" with a marine head, at least, if you're pumping overboard. That's to ensure that anything which might try to make itself into limestone in the lines, gets flushed all the way out of the boat--not just out of the bowl and into the plumbing.
There are worse things then flushing a few extra times.<G>
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20-03-2007, 12:35
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#14
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Registered User
Join Date: Feb 2007
Location: Seattle
Boat: Schock 35
Posts: 157
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For the stink in the bowl from dead marine life in the salt water just squirt in some "CP" made by Raritan Engineering. It will clean the bowl and the enzymes will take care of the bacterial smell. For "crystals" in the hoses etc. Two cups of distilled white vinegar followed with a thorough flush will clean out the calcium carbonate. Never, never use chlorine or bleach.
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20-03-2007, 14:35
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#15
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Moderator Emeritus
Join Date: Mar 2003
Location: Hayes, VA
Boat: Gozzard 36
Posts: 8,700
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Quote:
Never, never use chlorine or bleach.
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Bleach will kill the good bacteria that digest the waste inside the tank and it's about the worst thing for your tubes too. Bleach is very bad in the head.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
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